Wastewater Surveillance for SARS-CoV-2 in Athens, GA

All Data

Sewage samples are collected weekly from water reclamation facilities that serve Athens Clarke County (WRF A and WRF B). Samples are tested to detect and measure SARS‑CoV‑2, the virus that causes COVID‑19.

We measure the virus by detecting two genes specific to SARS‑CoV‑2, the N1 and N2 nucleocapsid genes, using RT-qPCR. The N1 and N2 gene targets are measured and reported as a concentration, in number of gene copies per liter of wastewater. The theoretical Limit of Detection (LOD) is noted.

We predict that changes in the concentration of SARS‑CoV‑2 in wastewater will reflect the community trends of circulating COVID‑19 infections. The daily number of newly reported COVID‑19 cases in Athens-Clarke County (purple) appear alongside the 7-day moving average of new cases (yellow). Changes in SARS‑CoV‑2 in wastewater may precede changes in reported cases because of lags in clinical testing.

Weekly Data Update

Updated every Thursday
Please Note: We strive to get results for each week’s sample updated by 5:00 pm on Thursday however, to ensure quality of data occasional delays in the update may occur. We will post updated data as soon as we are able.

Sept 15

The September 15 update is experiencing a delay and will be posted by Friday Sept 18. We apologize for any inconvenience

Sept 8

This week, levels of SARS‑CoV‑2 for both targets at both plants continued to exceed 1 million copies of virus per liter of sewage. Average values were similar to concentrations from the prior week (September 1, 2020) with virtually no change in the average levels at WRF B and a 6% reduction at WRF A.

An important note about sample collection this week was that it occurred over the Labor Day holiday and may explain the slight reduction in viral concentration at the WRF A plant. Samples were collected between ~6:30 am Monday through 6:30 am Tuesday. The volume of wastewater flowing into WRF A decreased from 5.73 million gallons on September 1, 2020 to 4.96 million gallons on September 8, 2020. The collection area for WRF A includes the UGA main campus and Downtown Athens. We suspect that this week’s data point reflects the real-time effect of population movement on viral levels in wastewater. In other words, a closed campus and likely large number of people traveling reduces the input. Samples collected on a particular day reflect the inputs of that day and not necessarily the entire week.

Our trend analysis suggests a continued elevation in total viral load (see data trends tab).

Daily reported cases in Clarke County continue to rise, now reaching a 7-day moving average of 126.1 new cases per day.

Sept 1

This week continues the trend of the past month with SARS‑CoV‑2 concentrations increasing in wastewater. Levels increased to their highest point since the beginning of data collection with average concentrations for both plants and both targets exceeding 3 million copies of virus per liter of sewage, approximately 10-fold higher than the prior week. Daily reported cases in Clarke County also continued to rise reaching a 7-day moving average of >74 cases per day.

Aug 25

SARS-CoV-2 concentrations in Athens-Clarke County wastewater increased slightly in this week’s samples (reaching >900,000 copies of the virus per liter of sewage). This moderate increase continues the upward trend observed over the prior three weeks. Reported cases have remained steady through the week (8/18 - 8/25/2020) averaging ~30 new cases per day.

Aug 18

On August 18, 2020, the concentration of SARS‑CoV‑2 increased to over 100,000 copies per liter for both gene targets. This uptick is somewhat reflected in the daily reported cases for Athens-Clarke county and may indicate further increases in the coming weeks.

Furthermore, this week marks the return of approximately 30,000 undergraduate students to the UGA main campus for the start of the fall semester.

Prior to Aug 18, 2020

Weekly analyses of SARS‑CoV‑2 in sewage began June 16, 2020, at which time concentrations were below the current method limit of detection and new cases were reported at <10 per day. Reported cases began to increase to >20 per day in late June and SARS‑CoV‑2 concentration increased to up to 10 million viral copies per liter. Sewage concentrations were steady through mid-July inline with newly reported cases averaging 35 per day. Beginning July 21, 2020 SARS‑CoV‑2 concentrations in sewage began to decline through early August, while concurrent case report remained high. We suspect that this decline possibly preceded the decline in cases noted in late August, which may be due to lags in testing results and case reporting.

Since August 4, 2020 SARS‑CoV‑2 concentration has steadily increased for both the N1 and N2 gene targets. This suggests that sewage concentrations may be a leading indicator for new cases in the community, but more data collection and monitoring of delays in testing reports will be needed to confirm this trend.

Research Overview

Purpose

Wastewater surveillance is an emerging tool for monitoring disease outbreaks. Coupled with clinical surveillance, wastewater surveillance can be used to estimate the level of viruses circulating in local population.

To better understand the outbreak of the novel Coronavirus disease-19 (COVID‑19) on a local level, we are monitoring wastewater samples from water reclamation facilities in Athens, GA. Wastewater samples are collected weekly and tested to detect the disease-causing virus, SARS‑CoV‑2.

Each sample is a composite of the wastewater received by the water reclamation facility in a single day. By examining these samples, we are capturing a snapshot into the health of the entire community that contributes to the sewershed. This wastewater-based research provides a new approach to epidemiology; sewage surveillance may be used to predict the total burden of disease at a community-scale, without extensive clinical sampling.

We are sharing here some of the preliminary results of our wastewater monitoring program. Our objective is to critically examine the use of SARS‑CoV‑2 wastewater-based epidemiology for the detection and surveillance of SARS‑CoV‑2 in our local community.

We are developing and evaluating our methods in real-time. We will share with you our weekly results and newest developments. This data is intended to complement clinical-based COVID‑19 surveillance data, that will together, inform public health decisions.

To learn more about national surviellence efforts, using wastewater-based epidemiology, please visit the CDC’s National Wastewater Surveillance System (NWSS).

Methods

Since May 2020, sewage samples have been collected weekly from the water reclamation facilities (WRFs) that serve Athens-Clarke County. Samples are collected from a 24-hour composite of the influent wastewater received by each WRF.

Samples are processed by the Lipp Laboratory at the University of Georgia to detect and measure the abundance of SARS‑CoV‑2 virus in wastewater.

Viral RNA, the genetic material of the SARS‑CoV‑2 virus, is extracted from each sample using the QIAmp Viral RNA Mini Kit.

The viral RNA is then measured using Real-Time RT-PCR Assays, following the CDC’s test protocol for the N1 and N2 SARS‑CoV‑2 nucleocapsid genes.

The N1 and N2 gene targets are measured and reported as a concentration, by the number of gene copies measured per liter of wastewater.

Reported case data for COVID-19 has been collected from Georgia’s Department of Public Health and summarized by Mark Ebell, MD, MS here.

A more detailed explanation of the research methods can be found here.

About

This weekly monitoring is conducted in partnership between Athens-Clarke County Utilities, the Lipp Laboratory, and the College of Public Health at the University of Georgia.

Team

Dr. Erin Lipp

Megan Lott, PhD Student

William Norfolk, PhD Student

Megan Robertson, PhD Student

For more information about our team and other ongoing research please visit the Lipp Laboratory website.

Data Trends

The total viral load of SARS‑CoV‑2 in the sewershed was estimated using data from our weekly wastewater monitoring. Sewage samples are collected weekly from two of the three water reclamation facilities that serve Athens Clarke County (WRF A and WRF B). Samples are tested to detect and measure SARS‑CoV‑222, the virus that causes COVID‑19.

The total viral load of SARS‑CoV‑2 is estimated by adjusting for the total wastewater volume collected by each water reclamation facility. The estimate is expressed as a sum of the total number of gene targets detected between the two facilities.

The trendlines below reflect the estimated total viral load of SARS‑CoV‑2 in the sewershed. The viral load is estimated by the N1 (green) and N2 (orange) gene targets. Data trends were calculated using locally estimated scatterplot smoothing (LOESS). The error associated with these estimates (the 95% confidence interval) is displayed.

Dashed lines indicate significant events that may affect local public health. On June 24, 2020 Georgia continues broad reopening, including bars. July 9, 2020 Athens-Clarke County implements mask mandate. On August 20, 2020 classes begin at the University of Georgia.

We predict that changes in the concentration of SARS‑CoV‑22 in wastewater will reflect the community trends of circulating COVID‑19 infections. The daily number of newly reported COVID‑19 cases in Athens-Clarke County (purple) appear alongside the 7-day moving average of new cases (yellow).